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• Image ransfer using hessian protocol from client's folder to tomcat server

  - by ?? ?

  My goal is to upload a image(.jpg or .png)from client's folder to tomcat6 server through hessian protocol. And do image processing using opencv on server, then return the image back to client. Question1. Is the following transfering steps correct? put a test.jpg image on client's folder -- convert the test.jpg in client.java(main.java) class to BufferedImage -- convert the BufferedImage to mat or Iplimage in server for using openCV.I have set a hello world sample from Simple Messaging Example using Hessian , and searched from Hessian with large binary data and other websites, but still dont know how to use it! Question2. Is there a related JAVA sample code? Thank you very much. Btw, I am using ubuntu12+netbeans7.2

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• Simple RIA backend

  - by Jeremy

  I'm creating a prototype for a java web application. Frontend is a Swing-based java applet. Backend should be a type of web-service, that is called by applet. Backend should run inside a servlet container and should have its own security (username/password) database. I know, that Tomcat has its own user database (realm), but the app should have own. Web-services, in turn, carrying out app logic and database access (via Hibernate). I'm a newbie for a web development and I'm getting lost in a huge amount of the java web frameworks. Even just reading 'introduction' and 'getting started' documents takes a lot of time. So I need an advice which framework(s) are suitable for the task and not very complex for a quick start. Thank you

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• getResourceAsStream() is always returning null

  - by Andreas Grech

  I have the following structure in a Java Web Application: TheProject -- [Web Pages] -- -- [WEB-INF] -- -- -- abc.txt -- -- index.jsp -- [Source Packages] -- -- [wservices] -- -- -- WS.java In WS.java, I am using the following code in a Web Method: InputStream fstream = this.getClass().getResourceAsStream("abc.txt"); But it is always returning a null. I need to read from that file, and I read that if you put the files in WEB-INF, you can access them with getResourceAsStream, yet the method is always returning a null. Any ideas of what I may be doing wrong? Btw, the strange thing is that this was working, but after I performed a Clean and Build on the Project, it suddenly stopped working :/

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• Enum : get the keys list

  - by Damien MATHIEU

  Hello, I'm not a java developer. But I'm currently taking a look at Android applications development so I'm doing a bit of nostalgy, doing some java again after not touching it for three years. I'm looking forward using the "google-api-translate-java" library. In which there is a Language class. It's an enum allowing to provide the language name and to get it's value for Google Translate. I can easily get all the values with : for (Language l : values()) { // Here I loop on one value } But what I'd want to get is a list of all the keys names (FRENCH, ENGLISH, ...). Is there something like a "keys()" method that'd allow me to loop through all the enum's keys ?

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• Error: cant find main class

  - by Vurb

  ok so im a newbie java dev using netbeans IDE 7.1.1 and im watching this tutorial and right off the bat i get an error in my program even after 5 retypes to make sure its exactly the same as in the video so anyways this is the error Error: Could not find or load main class javagame.JavaGame Java Result: 1 and this is the code i have written package JavaGame; import javax.swing.JFrame; public class JavaGame extends JFrame { public JavaGame(){ setTitle("java game"); setSize(500, 500); setResizable(false); setVisible(true); //setDefaultCloseOperation(); } public static void main(String[] args){ } }

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• Create Class objects based on type signature

  - by Andreas_D

  Class.forName(boolean.class.getName()); This doesn't work in Java - the virtual machine slaps you with a ClassNotFoundException. I was in need for something like that because I wanted to reflect methods based on Strings that included the method signatures, like public void doSomething(boolean yesWeCan, java.lang.String[] presidents); At the end I came up with a custom 'ClassFactory' which translates the type Strings to class objects. This factory includes a lot of handlers for primitive and array type values. The handler for array type objects is something like: if (isArrayOfObjects) { return Class.forName("L["+typeName.replace("[]", "")+";"); } My question is - have I missed something in the Java 1.5+ API that might do the trick?

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• Fastest way for inserting very large number of records into a Table in SQL

  - by Irchi

  The problem is, we have a huge number of records (more than a million) to be inserted into a single table from a Java application. The records are created by the Java code, it's not a move from another table, so INSERT/SELECT won't help. Currently, my bottleneck is the INSERT statements. I'm using PreparedStatement to speed-up the process, but I can't get more than 50 recods per second on a normal server. The table is not complicated at all, and there are no indexes defined on it. The process takes too long, and the time it takes will make problems. What can I do to get the maximum speed (INSERT per second) possible? Database: MS SQL 2008. Application: Java-based, using Microsoft JDBC driver.

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• How to compare two char* variables

  - by davit-datuashvili

  Suppose we have the following method (it is in c code): const char *bitap_search(const char *text, const char *pattern) My question is how can I compare text and pattern if they are char? This method is like a substring problem but I am confused a bit can I write in term of char such code? if (text[i]==pattern[i])? look i am interesting at this algorithm in java http://en.wikipedia.org/wiki/Bitap_algorithm how implement this in java? R = malloc((k+1) * sizeof *R); and please help me to translate this code in java

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• Does a servlet-based stack have significant overheads?

  - by John

  I don't know if it's simply because page-loads take a little time, or the way servlets have an abstraction framework above the 'bare metal' of HTTP, or just because of the "Enterprise" in Jave-EE, but in my head I have the notion that a servlet-based app is inherently adding overhead compared to a Java app which simply deals with sockets directly. Forget web-pages, imagine instead a Java server app where you send it a question over an HTTP request and it looks up an answer from memory and returns the answer in the response. You can easily write a Java socket-based app which does this, you can also do a servlet approach and get away from the "bare metal" of sockets. Is there any measurable performance impact to be expected implementing the same approach using Servlets rather than a custom socket-based HTTP listening app? And yes, I am hazy on the exact data sent in HTTP requests and I know it's a vague question. It's really about whether servlet implementations have lots of layers of indirection or anything else that would add up to a significant overhead per call, where by significant I mean maybe an additional 0.1s or more.

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• defualt parameter values in arguments and inheritance

  - by sil3nt

  Hello there, Im having trouble with some Java, How do I give in default parameter values in java?. for example I have this in c++ DVD(int i, string t, int y, string d="Unknown"): Items(i,t,y),director(d){} and in Java I tried public Dvd(int i, String t,int y, String d="Unknown"){ super(i,t,y); director = d; } which fails to build. So how do I go about giving in default values? also In my main testing class I tried giving in 3 arguments insead of 4 but this fails also. How do I get around this problem?.

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• Run Calculator in my App

  - by user

  I want to start the android calculator activity IN my activity. So, I can run an activity of my app in an activity of my app. But if I want to start an activity of the calculator for example in my app, logcat throws me this: FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{}: java.lang.SecurityException: Requesting code from com.android.calculator2 (with uid 10016) to be run in process (with uid 10044) Caused by: java.lang.SecurityException: Requesting code from com.android.calculator2 (with uid 10016) to be run in process (with uid 10044) How can I reach my goal to start the calculator activity in my activity? Thank you very much

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• How can I learn Android?

  - by Daisama

  I am a freshman in college which has been Java programming for over a year. I haven taken a couple of programming courses, both of which were with Java. And I have done web development for several years. So overall, I would't say that I am a complete beginner in programming. Recently, I have developed a strong interest in developing for Android. I read that Android development was with Java and I thought it would making development easier for me. But I was very wrong. Based on reviews from Amazon, I have begun reading "Professional Android Application Development by Meier but everything is going over my head. The Busy Coder's Guide to Android Development seems a bit more for my level but I still want everybody else's opinion. The Google stuff isn't very helpful to me at my level and neither are the tutorials on anddev and such. Any advice for a complete beginner on how to get started? Thanks.

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• Accessing data feed

  - by racket99

  I have a Java program on my desktop which displays financial data gleaned from the web. It is a 3rd party application. What I would like to do is intercept the data before it goes to the Java application and record it into a flat file for the purpose of later data analysis. Is this at all possible? I imagine the data are available and are entering my computer through some port which the Java app picks up and then displays. Help appreciated. Thanks

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• entity framework POCO template in a n-tiers design question

  - by bryan

  HI all I was trying to follow the POCO Template walkthrough . And now I am having problems using it in n-tiers design. By following the article, I put my edmx model, and the template generated context.tt in my DAL project, and moved the generated model.tt entity classes to my Business Logic layer (BLL) project. By doing this, I could use those entities inside my BLL without referencing the DAL, I guess that is the idea of PI; without knowing anything about the data source. Now, I want to extend the entities (inside the model.tt) to perform some CUD action in the BLL project,so I added a new partial class same name as the one generated from template, public partial class Company { public static IEnumerable AllCompanies() { using(var context = new Entities()){ var q = from p in context.Companies select p; return q.ToList(); } } } however visual studio won't let me do that, and I think it was because the context.tt is in the DAL project, and the BLL project could not add a reference to the DAL project as DAL has already reference to the BLL. So I tried to added this class to the DAL and it compiled, but intelisense won't show up the BLL.Company.AllCompanies() in my web service method from my webservice project which has reference to my BLL project. What should I do now? I want to add CUD methods to the template generated entities in my BLL project, and call them in my web services from another project. I have been looking for this answer a few days already, and I really need some guides from here please. Bryan

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• Windows mobile phone for business application - or design way out of scrolling problem

  - by Peter

  We have a business application written for Windows mobile. It has people doing inventories. The fastest way to do this is to keep one hand on the product being counted and the other on the phone. The five-way lets you hit enter to accept the current correct inventory (the norm) or to move one left to remove one. This is very fast. If I am two low, I have a quick glance at the phone- move my eyes back to count the next row - and with my right hand hit the five way "left left enter". Very fast. Our problem is that with I-Mate out of business, we cannot find a modern cell phone that has a decent size screen and a five way. Everyone is going to candy bar and flicks. That works great if it is two hands and you are looking at the phone, but not efficient for us. Other than the $1,500 ruggadized units, is there anybody who makes a business style Windows Mobile with a five way? If not, any ideas on how to design the phone to make it easier without a five way to quickly enter data like this?

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• Perl OO frameworks and program design - Moose and Conway's inside-out objects (Class::Std)

  - by Emmel

  This is more of a use-case type of question... but also generic enough to be more broadly applicable: In short, I'm working on a module that's more or less a command-line wrapper; OO naturally. Without going into too many details (unless someone wants them), there isn't a crazy amount of complexity to the system, but it did feel natural to have three or four objects in this framework. Finally, it's an open source thing I'll put out there, rather than a module with a few developers in the same firm working on it. First I implemented the OO using Class::Std, because Perl Best Practices (Conway, 2005) made a good argument for why to use inside-out objects. Full control over what attributes get accessed and so on, proper encapsulation, etc. Also his design is surprisingly simple and clever. I liked it, but then noticed that no one really uses this; in fact it seems Conway himself doesn't really recommend this anymore? So I moved to everyone's favorite, Moose. It's easy to use, although way way overkill feature-wise for what I want to do. The big, major downside is: it's got a slew of module dependencies that force users of my module to download them all. A minor downside is it's got way more functionality than I really need. What are recommendations? Inconvenience fellow developers by forcing them to use a possibly-obsolete module, or force every user of the module to download Moose and all its dependencies? Is there a third option for a proper Perl OO framework that's popular but neither of these two?

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• Seeking help with a MT design pattern

  - by SamG

  I have a queue of 1000 work items and a n-proc machine (assume n = 4).The main thread spawns n (=4) worker threads at a time ( 25 outer iterations) and waits for all threads to complete before processing the next n (=4) items until the entire queue is processed for(i= 0 to queue.Length / numprocs) for(j= 0 to numprocs) { CreateThread(WorkerThread,WorkItem) } WaitForMultipleObjects(threadHandle[]) The work done by each (worker) thread is not homogeneous.Therefore in 1 batch (of n) if thread 1 spends 1000 s doing work and rest of the 3 threads only 1 s , above design is inefficient,becaue after 1 sec other 3 processors are idling. Besides there is no pooling - 1000 distinct threads are being created How do I use the NT thread pool (I am not familiar enough- hence the long winded question) and QueueUserWorkitem to achieve the above. The following constraints should hold The main thread requires that all worker items are processed before it can proceed.So I would think that a waitall like construct above is required I want to create as many threads as processors (ie not 1000 threads at a time) Also I dont want to create 1000 distinct events, pass to the worker thread, and wait on all events using the QueueUserWorkitem API or otherwise Exisitng code is in C++.Prefer C++ because I dont know c# I suspect that the above is a very common pattern and was looking for input from you folks.

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• XML parsing design using xmlpp and C++

  - by shagv

  I would like to use an xml format similar to the following: <CONFIG> <PROFILE NAME="foobar"> <PARAM ID="0" NAME="Foo" CLASS="BaseParam"/> <PARAM ID="2" NAME="Bar" CLASS="StrIntParam"> <VALUE TYPE="STRING">some String</VALUE> <VALUE TYPE="INT">1234</VALUE> </PARAM> </PROFILE> </CONFIG> CONFIG contains a list of PROFILEs which contain a list of PARAMs which themselves can be any structure (to be defined in the future). The idea was to define classes that parsed each PARAM type and to keep track of which class to use in the PARAM's CLASS attribute. In code I have a config class that manages the list of profiles and a profile class that manages the list of params. I would like the profile class to handle additional param types (that inherit BaseParam) without modification to the profile class (or at the very least with minimal modification). First of all, is this design viable? If so, what are some ways I could use different param classes and have their creation at run-time be automatic (the profile class sees the CLASS attribute and knows which type to create)?

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• Fastest Method to Learn Web Design for a Developer

  - by hekevintran

  I am a Web developer and in my projects I have noticed that my weakest point is not being good at the front-end design. Relying on other designers can be annoying if they are not able to produce as quickly as I want. My perspective on HTML/CSS is that it is basically a big hack that amazingly works. There are too many CSS and browser specific bugs/quirks to learn and remember them all without spending extreme amounts of time trying to untangle everything. Is there a fast track route to getting CSS into my brain? I have looked at some CSS books, but to me they really read as long lists of how to render things correctly in IE6 and how to make corners rounded. (Seriously why does it require so many tricks to make a sharp corner round? On any platform but the Web this would be called a major oversight.) Does there exist something that does the analogous to CSS that jQuery does for JavaScript? Using jQuery you don't need to know JavaScript well to make things that work. I am not interested in learning why IE6 does things in weird ways because I don't care about supporting it at all. I am more interested in a method of learning how to use CSS to do what I want without spending hours and hours reading obscure blogs.

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• How would you design a question/answer view (iPhone SDK)

  - by Aurélien Vallée

  I'm new to iPhone development, and I have a question on how to create a view for my application. The view should display a problem (using formatted/syntax highlighted text), and multiple possible answers. The user should be able to click on an answer to validate it. Currently, I am trying to use a UITableView embedding UIWebView as contentView. That allows me to display formatted text easily. The problem is that it is a real pain to compute and adjust the height of the cells. I have to preload the webview, call sizeToFit, get its height, and update the cell accordingly. This process should be done for the problem and the answers (as they are HTML formatted text too). It's such a pain that I am planning to switch to something else. I thought using only a big UIWebView and design everything in HTML. But I looked at some articles describing how to communicate between the HTML page and the ObjectiveC code. This seems to involve some awful tricks too... So... that's it, I don't really know what I should do. I guess some of you dealt with such things before, and would provide some greatly appreciated tips :)

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• Need help with WCF design

  - by Jason

  I have been tasked with creating a set of web services. We are a Microsoft shop, so I will be using WCF for this project. There is an interesting design consideration that I haven't been able to figure out a solution for yet. I'll try to explain it with an example: My WCF service exposes a method named Foo(). 10 different users call Foo() at roughly the same time. I have 5 special resources called R1, R2, R3, R4, and R5. We don't really need to know what the resource is, other than the fact that a particular resource can only be in use by one caller at a time. Foo() is responsible to performing an action using one of these special resources. So, in a round-robin fashion, Foo() needs to find a resource that is not in use. If no resources are available, it must wait for one to be freed up. At first, this seems like an easy task. I could maybe create a singleton that keeps track of which resources are currently in use. The big problem is the fact that I need this solution to be viable in a web farm scenario. I'm sure there is a good solution to this problem, but I've just never run across this scenario before. I need some sort of resource tracker / provider that can be shared between multiple WCF hosts. Any ideas from the architects out there would be greatly appreciated!

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• Nested namespaces, correct static library design issues

  - by PeterK

  Hello all, I'm currently in the process of developing a fairly large static library which will be used by some tools when it's finished. Now since this project is somewhat larger than anything i've been involved in so far, I realized its time to think of a good structure for the project. Using namespaces is one of those logical steps. My current approach is to divide the library into parts (which are not standalone, but their purpose calls for such a separation). I have a 'core' part which now just holds some very common typedefs and constants (used by many different parts of the library). Other parts are for example some 'utils' (hash etc.), file i/o and so on. Each of these parts has its own namespace. I have nearly finished the 'utils' part and realized that my approach probably is not the best. The problem (if we want to call it so) is that in the 'utils' namespace i need something from the 'core' namespace which results in including the core header files and many using directives. So i began to think that this probably is not a good thing and should be changed somehow. My first idea is to use nested namespaces as to have something like core::utils. Since this will require some heavy refactoring i want to ask here first. What do you think? How would you handle this? Or more generally: How to correctly design a static library in terms of namespaces and code organization? If there are some guidelines or articles about it, please mentoin them too. Thanks. Note: i'm quite sure that there are more good approaches than just one. Feel free to post your ideas, suggestions etc. Since i'm designing this library i want it to be really good. The goal is to make it as clean and FAST as possible. The only problem is that i will have to integrate a LOT of existing code and refactor it, which will really be a painful process (sigh) - thats why good structure is so important)

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• Windows Workflow Foundation: Recommendations how to design architecture

  - by Petr Felzmann

  We are running several the same ASP.NET applications (one per customer) based on our custom framework (libraries). Each application use its own database (Initial Catalog in the term of connection string). Now we would like to add workflow capability (of course 4.0 ;) to the applications. So the particular workflows will be the same for all the applications only some initial settings of each workflow can vary, e.g. in one application the e-mail will be send to the user X, but in other application to the user Y. I have several general questions how to design architecture: (1) Can be the workflow database shared for all the applications? (2) Where to host workflow engine - inside our custom windows NT service or inside IIS? What are the criteria to choose the right host? (3) How the workflow engine should communicate with applications? Should application call some WCF endpoint API configured in workflow host or vice verse - should each application provide WCF endpoint API and workflow engine will call it? How then the workflow engine will identify applications? Both cases requires probably some application identifier as a parameter in API calls? (4) We would like to also store some information to the application databases based on the workflow states. Is it possible? Thanks for suggestions!

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• How to design a RESTful collection resource?

  - by Suresh Kumar

  I am trying to design a "collection of items" resource. I need to support the following operations: Create the collection Remove the collection Add a single item to the collection Add multiple items to the collection Remove a single item from the collection Remove multiple items from the collection This is as far as I have gone: Create collection: ==> POST /service Host: www.myserver.com Content-Type: application/xml <collection name="items"> <item href="item1"/> <item href="item2"/> <item href="item3"/> </collection> <== 201 Created Location: http://myserver.com/service/items Content-Type: application/xml ... Remove collection: ==> DELETE /service/items <== 200 OK Removing a single item from the collection: ==> DELETE /service/items/item1 <== 200 OK However, I am finding supporting the other operations a bit tricky i.e. what methods can I use to: Add single or multiple items to the collection. (PUT doesn't seem to be right here as per HTTP 1.1 RFC Remove multiple items from the collection in one transaction. (DELETE doesn't seem to right here either)

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• Applying policy based design question

  - by Arthur

  I've not read the Modern C++ Design book but have found the idea of behavior injection through templates interesting. I am now trying to apply it myself. I have a class that has a logger that I thought could be injected as a policy. The logger has a log() method which takes an std::string or std::wstring depending on its policy: // basic_logger.hpp template<class String> class basic_logger { public: typedef String string_type; void log(const string_type & s) { ... } }; typedef basic_logger<std::string> logger; typedef basic_logger<std::wstring> wlogger; // reader.hpp template<class Logger = logger> class reader { public: typedef Logger logger_type; void read() { _logger.log("Reading..."); } private: logger_type _logger; }; Now the questing is, should the reader take a Logger as an argument, like above, or should it take a String and then instantiate a basic_logger as an instance variable? Like so: template<class String> class reader { public: typedef String string_type; typedef basic_logger<string_type> logger_type; // ... private: logger_type _logger; }; What is the right way to go?

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